Electronic components each including a spiral-shaped conductor (spiral conductor) and an extended conductor that contain Ag and are disposed within a body containing glass have been proposed. Among those electronic components, a number of components that may increase reliability of connection with external electrodes without compromising reliability in insulation have been proposed (for example, Japanese Unexamined Patent Application Publication No. 2013-135109).
Japanese Unexamined Patent Application Publication No. 2013-135109, for example, discloses a common mode noise filter including a multilayer body having a plurality of insulating layers stacked, an external conductor on the external surface of the multilayer body, and a first coil and a second coil within the multilayer body. In this common mode noise filter, the first and second coils each include a spiral-shaped conductor and an extended conductor connecting the spiral-shaped conductor with the external conductor. According to Japanese Unexamined Patent Application Publication No. 2013-135109, the reliability of connection between the spiral-shaped conductor and the external electrode in the common mode noise filter (or common mode choke coil) can be increased by forming the extended conductor to have a thickness larger than the thickness of the spiral-shaped conductor. The insulating layers of the multilayer body are made of an insulating material containing glass.
In electronic components such as common mode choke coils including an Ag-containing spiral-shaped or extended conductor on a glass-containing insulating layer, the Ag in the conductors is likely to diffuse into the glass by firing in the manufacturing process of the electronic component. This is a cause of initial problems with insulation reliability, such as a decrease in insulation resistance (IR). On the other hand, if Ag diffusion is prevented, connection reliability between the extended conductor and the external conductor is decreased.